WireWeHere said:

However, can I run a 4.0mm radial (unfused) off the ring as a 4.0mm radial is rated to carry 32A (single phase)?

Not by simply connecting into a double socket-outlet as you have shown, because the terminal capacity in BS 1363 doesn't support sufficient cross-sectional area. Some manufacturers' terminals might be up to it. but definitely not a "standard approach" because of that.

The standard terminal capacity for BS 1363 series accessories on the fixed wiring side is that the terminal must be capable of terminating each of the following combinations: 3 no. 2.5 sq mm conductors, 2 no. 4.0 sq mm conductors, or 1 no. 6 sq mm conductor.

2 no. 2.5 sq mm conductors with a spur of 1 no. 4 sq mm conductor exceeds this terminal capacity.

WireWeHere said:

However, can I run a 4.0mm radial (unfused) off the ring as a 4.0mm radial is rated to carry 32A (single phase)?

Not by simply connecting into a double socket-outlet as you have shown, because the terminal capacity in BS 1363 doesn't support sufficient cross-sectional area. Some manufacturers' terminals might be up to it. but definitely not a "standard approach" because of that.

The standard terminal capacity for BS 1363 series accessories on the fixed wiring side is that the terminal must be capable of terminating each of the following combinations: 3 no. 2.5 sq mm conductors, 2 no. 4.0 sq mm conductors, or 1 no. 6 sq mm conductor.

2 no. 2.5 sq mm conductors with a spur of 1 no. 4 sq mm conductor exceeds this terminal capacity.

But you could of course achieve the same effective topology using a joint box, or even a few wagos in the back of the socket. (In some parts of the world, accessories often accept a single conductor per terminal and wire-nuts or similar in the back box for looping or spurring is the normal approach.)

   - Andy.